E39 Close Reach 8.1 kts

[G Kiba]

weatherhelm

Didn't see a mention in any of the other posts... Check your mask rake?
The weatherhelm on my E27 was reduced significantly by adjusting he rake back. I dropped the mast last Fall to make some spreader repairs. I re-rigged from scratch and wow. What a difference.

 

[Ryan L]

Sold! I was stationed at North Island and lived in PB for a few years. I sometimes wonder why I ever left! We sailed in the bay a few years ago and loved every bit of it.

I did some math off the chart plotter and I can't get an exact distance between what we traveled and the distance between way points. 2.61nm between start and mark, we traveled somewhere around 2.65nm, the track points being too coarse to get an exact number with the XTE to windward not leeward. We averaged 7.34kts with a low of 6.0kts at the start (I broke part of the primary self tailer right at the start) and the aforementioned 8.1kts midway.

For sure we need to reduce weatherhelm, but I know I can't sail that speed if I'm flat. There has to be a spot of perfection in there somewhere. Lisa and I talked about it over dinner and she insists that we reduce the heel. Smart woman she is.

Chris

The bay is still here waiting for you!

Just for clarification, when I write "flat is fast" I don't literally mean zero heel. What I mean is no excessive heel. It's just more catchy to say "flat is fast" than "no excessive heel is fast."

On the leg you're analyzing how many tacks did it take to reach the mark?

 

[Mort Fligelman]

Effects of excessive heeling

Early in my sailing and racing endeavors I asked a friend....who was also my sailing "MAVEN", and had the credentials go along with it, why heeling over to far slowed the boat......

His answer...."when your boat is on the hard take a good look at what the hull looks like in the water every 5 degrees you heel!"

I think it still applies today....FWIW......and my 0.02 worth

 

[gadangit]

The bay is still here waiting for you!

Just for clarification, when I write "flat is fast" I don't literally mean zero heel. What I mean is no excessive heel. It's just more catchy to say "flat is fast" than "no excessive heel is fast."

On the leg you're analyzing how many tacks did it take to reach the mark?

Tacks? It is a drag race to the mark. None! It would have been downright embarrassing if one needed a tack on a leg where the wind is almost 90 degrees true to the course.

 

[gadangit]

Didn't see a mention in any of the other posts... Check your mask rake?
The weatherhelm on my E27 was reduced significantly by adjusting he rake back. I dropped the mast last Fall to make some spreader repairs. I re-rigged from scratch and wow. What a difference.

Hi Grant-
We don't have a backstay adjuster, sacrilege on a boat that is racing I know. We are really a cruising boat that is just out trading paint in the local regattas. We also don't have the original mast and the z-spar we have has been described as an unbending telephone pole. When we had our sails made I made it clear to the sailmaker that we would not have a backstay adjuster and to design accordingly. The sailmaker is a very good racer and didn't think that was a good idea. Oh well, one less tool to shape the main, one less thing to maintain.

Chris

 

[gadangit]

Early in my sailing and racing endeavors I asked a friend....who was also my sailing "MAVEN", and had the credentials go along with it, why heeling over to far slowed the boat......

His answer...."when your boat is on the hard take a good look at what the hull looks like in the water every 5 degrees you heel!"

I think it still applies today....FWIW......and my 0.02 worth

Hi Mort-
The one thing to consider in the E39 hull shape is that it was designed back when the IOR rules punished for waterline and it appears that the work around was to plan for a certain level of heel to increase the waterline under sail. We have a noticeable tumblehome and a relatively narrow stern which looks to me that benefits from a heel by increasing the waterline length. Obviously there is a limit to the gains and other forces that come into play when heeling. Ryan had linked to an article earlier in the thread that did a good job describing hull shapes over the years and why they were designed that way. Interesting read for sure.

Chris

 

[G Kiba]

gadangit,

Backstay adjustment is usually applied to tension the fore stay (clean up the head sail). Rake is controlled with adjustments to the standing rigging. Just a suggestion. Adjusting the rake on my boat made a world of difference when it came to weather helm. I use to fight the helm a lot. Now the boat heads up in a gust but is very controllable. It's on a "Whole nuther level" now.

 

[Guy Stevens]

The original was a telephone pole too

Actually I have seen a number of telephone poles that have more bend than a Ericson 39 mast.

The backstay adjuster on a 39 (most came with one by the way, that has since been discarded, a shame since they were nice units), tensions or slacks the jibstay for upwind or downwind work. There is no bend adjustment on a standard 39 mast, because there is no bend.

You had a lot of sail up for the conditions. You were over canvased by your own admission. I understand why, not wanting to mess with something that seemed to be working, coupled with a short handed crew. Next time try less sail area, and I think you will be surprised with the increase in speed.

Guy

 

[Ryan L]

Tacks? It is a drag race to the mark. None! It would have been downright embarrassing if one needed a tack on a leg where the wind is almost 90 degrees true to the course.

Ah... I assumed you were beating. Still, I agree with Guy and others than you would have likely been faster with less sail and less heel. Just curious, have you considered adding a canting keel and water ballast?




...kidding

 

[gadangit]

Ah... I assumed you were beating. Still, I agree with Guy and others than you would have likely been faster with less sail and less heel. Just curious, have you considered adding a canting keel and water ballast?




...kidding

Ha!! Can you imagine trying to maintain all that?

I went out yesterday and sailed with the asymmetrical spinnaker to test some things. We had 5-10kts and pretty flat water. On a reach I was able to power up to 7.5kts briefly, but we averaged closer to 7.2 on the reaching runs. What I found interesting was the boat was essentially flat and you could actually see the boat created wave next to the hull that the boat is trying to climb, obviously to no avail. I have to admit to being an engineer, so I'm familiar with the difference between theory and application. What puzzles me is how I'm supposed to make a boat go faster than it's theoretical hull speed.

The vast majority of my sailing experience has been on boats that I didn't care about this (hunter 36, catalina 30), j-80's (will far exceed it's theoretical hull speed on a plane), j-105 (will plane on a reach, polars show 9.89kts @135AWA) and F18(multi-hull, I laugh at displacement hulls.)

So, someone school me on how this works. My position is that this hull was designed to heel to a point where the effective waterline length will allow a higher theoretical maximum hull speed.

Chris

 

[Christian Williams]

I can't school anybody, but here's my experience:

--It's impossible to get accurate speed numbers to decimal points, and comparing them, and trying to analyze them will drive you (me) crazy. For me, indicated speed is good for faster or slower when changing sails or courses, but only briefly and relatively.

--The way you sail the boat--heel, pointing, sail area, helm technique--trumps many other factors. And the way you sail it fast is so dependent on conditions of wind, chop, current that it can only be learned in head to head racing competition, and is probably specific to individual boats and sets of sails and sail inventories.

--Whatever the theoretical benefits of heeling to increase waterline length, heeling implies wind and waves. Any momentary overpowering, not just a knockdown, probably wipes out the advantage. Sudden helm corrections are bad, and the best helmsmen avoid having to make them, and often sail to windward somewhat feathered to avoid getting caught.

--Surfing changes everything.

 

[steven]

increasing hull speed by healing to get more waterline is a small effect. For 30ft DWL, Maybe from 7.1 hull speed to 7.3 or so. If you gain the waterline by creating even a little bit more frictional drag it may not be worth it. This effect cannot account for hitting 8+kts.

I believe displacement boats can exceed hull speed - if you have abnormally lots of power.

you can sometimes tell if you are making leeway by looking off your weather stern quarter. If you see large swirling eddies, you are probably going sideways.

yes it is possible to make leeway to weather - sort of. Round bottom dinghy can do a roll-tack - a slow tack around the radius of a circle - as the boat passes through flat on it's way to heeling on the other side, it may still have a bit of forward momentum and skid (a very little bit) upwind. I have tried this in 35-2 - I think it works (but hard to tell).

--Steve

 

[Dave N]

39 and 46 owners

There are very few pics of the 39 and 46 on our site. Please consider putting some here.

http://www.ericsonyachts.org/infoexchange/group.php?groupid=3

 

[Seth]

Hull speed

Ha!! Can you imagine trying to maintain all that?

I went out yesterday and sailed with the asymmetrical spinnaker to test some things. We had 5-10kts and pretty flat water. On a reach I was able to power up to 7.5kts briefly, but we averaged closer to 7.2 on the reaching runs. What I found interesting was the boat was essentially flat and you could actually see the boat created wave next to the hull that the boat is trying to climb, obviously to no avail. I have to admit to being an engineer, so I'm familiar with the difference between theory and application. What puzzles me is how I'm supposed to make a boat go faster than it's theoretical hull speed.

The vast majority of my sailing experience has been on boats that I didn't care about this (hunter 36, catalina 30), j-80's (will far exceed it's theoretical hull speed on a plane), j-105 (will plane on a reach, polars show 9.89kts @135AWA) and F18(multi-hull, I laugh at displacement hulls.)

So, someone school me on how this works. My position is that this hull was designed to heel to a point where the effective waterline length will allow a higher theoretical maximum hull speed.

Chris

Chris,
While there is certainly a relationship between WL length and potential speed, is is NOT an absolute limiting factor. I believe the complete correct term is "theoretical hull speed", and this is for a reason. Most boats can exceed hull speed under the right conditions. As for heeling, yes, you get some added length when you heel, which will increase the speed potential, but there is a point of diminishing returns where weather helm (and hence rudder drag) becomes too much and the hull shape is no longer what is was designed to be, and added leeway does not help either (leeway is hard to measure on a 2 miles leg). Any more than about 15 degrees is not going to help your speed, of that I am sure. I think people make much too much about the relationship between WL length and hull speed-as this is a guideline, but does not describe your max speed limit. It is true that the "power" needed to significantly exceed "hull speed" is much more than that needed to reach it, but you see displacement power boats do it all the time-albeit at high rpm's and fuel burns. For a sailboat this "power" can come from higher wind speeds at the right angles and sail area and surfing waves..I am NOT an engineer so can't provide the math, but you have a very conventional and fast boat for it's length and displacement. Sail it like you stole it (but not too overpowered) and have fun!

S

 

[Ryan L]

Chris,
While there is certainly a relationship between WL length and potential speed, is is NOT an absolute limiting factor. I believe the complete correct term is "theoretical hull speed", and this is for a reason. Most boats can exceed hull speed under the right conditions. As for heeling, yes, you get some added length when you heel, which will increase the speed potential, but there is a point of diminishing returns where weather helm (and hence rudder drag) becomes too much and the hull shape is no longer what is was designed to be, and added leeway does not help either (leeway is hard to measure on a 2 miles leg). Any more than about 15 degrees is not going to help your speed, of that I am sure. I think people make much too much about the relationship between WL length and hull speed-as this is a guideline, but does not describe your max speed limit. It is true that the "power" needed to significantly exceed "hull speed" is much more than that needed to reach it, but you see displacement power boats do it all the time-albeit at high rpm's and fuel burns. For a sailboat this "power" can come from higher wind speeds at the right angles and sail area and surfing waves..I am NOT an engineer so can't provide the math, but you have a very conventional and fast boat for it's length and displacement. Sail it like you stole it (but not too overpowered) and have fun!

S

Seth nailed it. Thanks for posting that.